I know you like to work in the analog domain, but couldn't you work your analog/tube Zen magic by modding an existing DAC like you have with your CD player products? For example, something with a large enough chassis to allow you room for extra tube circuitry.

You're leaving out the PC/disc-less audio users (like me) who don't own a CD player.

Or is there some reason I've not thought about?

thanks, -Brad-

P.S. I live in Brazil temporarily now and had to rip all my hundreds of CD's to FLAC files on a hard drive I could bring down here and I use a USB DAC.

There are also products like the Trends UD-10.1 that allow the PC to "look like a CD transport"

They have some pretty bold claims, as one might expect of a mfg'er...

"On the other hand, Trends UD-10.1 upgrades your PC/Mac to be a hi-end audio source. Thanks to the excellent power supply handling, the high accuracy clock and the sophisticated digital output circuit, the Trends UD-10.1 makes your PC/Mac to behave as a high-end CD transport to work with an external DAC. Yet, the Trends UD-10.1 and PC/Mac combination provides better sound quality, larger storage capacity and a more user-friendly interface than most standard CD players. (Remarks: computer hard disk is far superior to a CD player, no matter the speed, stability, error correction, jitter reduction. They are actually the technology of different eras.) "

The reason is very simple. I don't build products unless I feel I can clearly offer a superior result.

So far there are at least 200 choices out there, many of them aren't half bad. Behind the scenes since 2003, I have invested plenty in R&D on DACs, and even built a hand full of prototypes. Being a digital product, any engineer can read the spec sheet for a given chip set and throw together a dac (probably why there are so many choices out there) but I don't see too many of them building superior sounding amplifiers which I feel is my specialty.

I built a good Burr Brown DAC for the ZCD player during it's development to compare it against the on board chip set in the player and found the variable of the digital IC, and the required re-clocking to sound less appealing than the stock chip set in the player.

Bottom line where DACs are concerned, unless you want to promise me sales for a $7500 no holds barred effort, what is already out there is good enough. It's the output stage of the DAC that makes the BIG difference, and where most fall short. Sticking a ZBOX on any good DAC is usually all that is required.

So far on the digital end, my R&D has taken me through a variety of chip sets and approaches and what I've learned is the brick wall filter is what creates the "digital sound" and is I feel a classic "math guy" mistake made by almost all engineers who design them. Personally, I feel the non-oversampling DACs show the most potential at this point in time.

Thanks for the reply/info Steve. I was thinking about the ZBox as potential aid or solution. I just am not a fan of extra boxes/connectors. I suppose if you offered the ZBox in kit form, people could potentially DIY mod their DAC's to include it - if the box has enough space of course.